Clear vs. Cloudy Wort Gravity

[Nosybear]

All, a while back I remember a thread asking whether the gravity of wort with protein still in suspension was different than the same wort clear. Well, I got a data point this weekend. I took the gravity of my Kentucky Common with a refractometer immediately after the boil, cooled, and got 1.053. Later I took the gravity again once the cold break had settled out and got 1.050. Can't generalize from one point but it seems that the protein in suspension in wort contributes to the gravity.

 

[Aub]

All, a while back I remember a thread asking whether the gravity of wort with protein still in suspension was different than the same wort clear. Well, I got a data point this weekend. I took the gravity of my Kentucky Common with a refractometer immediately after the boil, cooled, and got 1.053. Later I took the gravity again once the cold break had settled out and got 1.050. Can't generalize from one point but it seems that the protein in suspension in wort contributes to the gravity.

I had a similar experience brewing a California Common last weekend, my initial reading was 1.060 and the second reading was 1.056.
It does seem that the protein in suspension contributes to the gravity.

 

[Hawkbox]

I find if I leave the wort on the refractometer for a while it changes a bit. Also my hydrometer dropped the longer I left it, I don't have agood way to chill the wort for the hydrometer quickly yet though. so it may just be cooling.

 

[Hogarthe]

I find if I leave the wort on the refractometer for a while it changes a bit. Also my hydrometer dropped the longer I left it, I don't have agood way to chill the wort for the hydrometer quickly yet though. so it may just be cooling.

If its cooling the hydrometer will change. You need a temp correction chart to see what the gravity is if not reading the hydrometer at the specified temperature. So if the temp changes the reading will as well.

 

[Hawkbox]

Yeah, I figured as much but there are factors in play that we have to account for is more my point.

 

[Nosybear]

I find if I leave the wort on the refractometer for a while it changes a bit. Also my hydrometer dropped the longer I left it, I don't have agood way to chill the wort for the hydrometer quickly yet though. so it may just be cooling.

I've observed that effect as well - the gravity goes up a couple of points while the wort cools. At least I hope it's cooling - can't cross-check with the hydrometer because as the wort is cooling, protein is precipitating out, moving the needle the opposite direction as the cooling. As long as you measure consistently, though, you should be okay.

 

[GFHomebrew]

@jeffpn did a thread on trub in hydrometer i remember that showed shows trub skews hydri reading.

When doing hydro reading i take preboil and slap it in glass measuring jar in freezer and come back once cooled and pour off a clear hydro sample and use BF hydrometer calibration if sample still above hydro calibration temp of 20c.

One day ill grab one of them refractometers for them quick boil checks but this shows they must give you a close gravity check vut not spot on.